<!DOCTYPE html>
<head>
<script>
  function addRules() {
    const script = document.createElement('script');
    script.type = 'speculationrules';
    script.innerText = `
      {
        "prerender": [
          {"source": "list", "urls": ["target.html"]}
        ]
      }
    `;
    document.head.append(script);
  }
</script>
</head>
<body>
  <button onclick="addRules()">add rules</button>
  <a href="target.html">test</a>
</body>
